In the first photograph the main subject isn't distinct enough because of the branch that's about the same size directly behind it. Even though I have repetition of lines (the other branches) their position in the photo isn't ideal. The main subject is just kind of swallowed up and not very interesting.
In the second photo I see a bit of color coming in with some blue and a bit of red in the background. So, I like that element. However, there are now two branches competing for your attention and they're about the same size again as the subject. My eye is pulled to the upper left corner and there's nothing there of interest. I need to make an adjustment and bring your attention back to the branch with the lichen on it.
The last photo is more pleasing because the subject is the center of attention. There's still some of the color that we saw in the last photo and there's still repetition of shapes (the line of the branches), but now the lichen on the center branch takes precedence and the other elements serve to support it rather than detract from it.
